The invention relates to a metal stamping and more specifically to the formation of relatively thin gauge stainless steel rings having radially spaced corrugation in the ring. A plurality of these rings are placed alternately in a stack with totally flat rings placed between them with the corrugation providing a series of small openings for a gas burner utilized in camping stoves. Burners of this type have been sold in the marketplace for years. The old method of forming these corrugated rings was to stamp the rings first in flat form and then individually place each flat ring between a pair of mating radial corrugated dies to form the corrugations. The new method basically reverses the process in that it first stamps the radial corrugations in an annular area of sheet stock and then punches out the ring parts with dies which are not flat, but rather corrugated on their mating cutting surfaces so the previously formed corrugations are not flattened during cutting of the rings.
The general idea of utilizing a kidney-shaped slot for maintaining alignment of a part within a sheet while additional stamping operations are made is generally taught in the patent to Grieb, U.S. Pat. No. 4,958,430. The idea is also generally taught in the patent to Brown, No. U.S. Pat. No. 3,460,368, wherein the kidney slot 69 and center hole 65 are removed prior to the final curvature stamping of the washer.